JP3619533B2 - Refrigeration equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a refrigeration apparatus in which a sensor is attached to a heat exchange pipe (for example, a U-shaped tube) of a heat exchanger.
[0002]
[Prior art]
Japanese Utility Model Publication No. 5-19725 discloses an air conditioner (refrigeration apparatus) in which a sensor is provided in a U-shaped tube of a heat exchanger.
In the air conditioner shown in this publication, a cylindrical sensor holder is attached to a U-shaped tube on the side of a heat exchanger, and the sensor is inserted into the holder.
[0003]
In this way, the sensor is attached to the heat exchanger, the temperature of the heat exchanger is detected by this sensor, and the amount of refrigerant flowing in the air conditioner is controlled.
[0004]
[Problems to be solved by the invention]
Here, when the heat exchanger in which the heat exchange pipes are stacked in the upper and lower stages is used as a condenser, and the above-described sensor is attached to the lower heat exchange pipe, the following problems occur. I understood it.
That is, although a collecting pipe is provided on the outlet side of the heat exchange pipe, the refrigerant pressure in the lower heat exchange pipe is reduced by the pressure resistance of the upper heat exchange pipe due to the pipe resistance and gravity of the collecting pipe. Lower than.
[0005]
Therefore, the liquid refrigerant condensed in the heat exchanger is more likely to accumulate in the lower heat exchange pipe than in the upper heat exchange pipe. Thus, if the sensor is provided in the lower heat exchange pipe in which the condensate refrigerant tends to accumulate, the temperature of the gas refrigerant in the heat exchanger cannot be accurately detected. In other words, since the temperature change of the liquid refrigerant is smaller than the temperature change of the gas refrigerant, the opening degree control of the expansion valve based on the detection value of this sensor cannot take a sufficient range of the opening degree. It was.
[0006]
In addition, when the liquid refrigerant accumulates in this heat exchanger, the heat exchange rate in the accumulated portion is extremely inferior to the heat exchange rate in the portion where the gas refrigerant accumulates. The decline could not be denied.
In the present invention, when a heat exchanger having heat exchange pipes arranged in a stacked state in a plurality of upper and lower stages is used as a condenser, the amount of liquid refrigerant stored in the heat exchanger is reduced and the heat The purpose is to suppress a decrease in the heat exchange efficiency of the exchanger.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the present invention allows the gas refrigerant discharged from the compressor to flow to the respective heat exchange pipes of the condenser via the flow divider, and the refrigerant condensed by these heat exchange pipes is collected in the collecting pipe. In the refrigeration system that is decompressed by the expansion valve and led to the evaporator after the compilation , these heat exchange pipes meander in the same shape in the condenser, and these heat exchange pipes are stacked up and down. A sensor for controlling the opening degree of the expansion valve is provided in the upper heat exchange pipe connected to the collecting pipe, and the opening degree of the expansion valve is controlled based on a value detected by the sensor. It is what I did.
[0008]
[Action]
Since the refrigerant detected by this sensor is gaseous, the temperature of the refrigerant is quickly detected to control the opening of the expansion valve. This control makes it difficult for liquid refrigerant to accumulate in the condenser.
[0009]
【Example】
In FIG. 1, 1 is an indoor unit of a built-in type air conditioner (refrigeration apparatus) installed behind the ceiling, and is connected via an outdoor unit 2 and a refrigerant pipe 3 shown in FIG.
The indoor unit 1 includes a blower 4, an indoor heat exchanger 5 located on the leeward side of the blower, a flow divider 6, a collecting pipe 7, an electric expansion valve 8, and a drain pan 9. . Reference numeral 10 denotes a discharge port, which is provided with a cylindrical flange member 11 for attaching a duct (not shown). Reference numeral 12 denotes a suction port. 13 is a panel arranged along the ceiling surface 14, and a suction grill 15 connected to the suction port 12 is provided.
[0010]
The refrigerant piping relationship of the indoor heat exchanger 5, the flow divider 6, the collecting pipe 7, etc. will be described later.
And by operation | movement of the air blower 4, indoor air flows like a solid line arrow, and after adjusting temperature (cooling and heating) with the indoor heat exchanger 5, it discharges from the discharge port 10, and passes through a duct which is not shown in figure. Has been led to.
[0011]
In FIG. 2, the outdoor unit 2 contains a compressor 20, a four-way valve 21, an outdoor heat exchanger 22, a flow divider 23, a collecting pipe 24, and an accumulator 25.
During cooling, the four-way valve 21 is set to a solid line state, so that the refrigerant discharged from the compressor 22 flows as indicated by a solid line arrow. The outdoor heat exchanger 22 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator, and the indoor heat exchanger 5 cools the room.
[0012]
On the other hand, during heating, the refrigerant discharged from the compressor 20 flows as indicated by broken line arrows by setting the four-way valve 21 to the broken line state. The indoor heat exchanger 5 acts as a condenser and the outdoor heat exchanger 22 acts as an evaporator, and the room is heated by the action of the indoor heat exchanger 5.
Here, in general, an air conditioner in Japan has a larger heating capacity than a cooling capacity due to the Japanese climate. In order to set in this way, the outdoor heat exchanger 22 is made larger than the indoor heat exchanger 5 because it is necessary to increase the evaporation capacity of the outdoor heat exchanger 22 during heating, that is, the amount of heat generated.
[0013]
Specifically, the inner diameter of the heat exchange pipe of the outdoor heat exchanger 22 is set to 9.52 mm, the inner diameter of the heat exchanger pipe of the indoor heat exchanger 5 is set to 7 mm, and the outdoor heat exchanger 22 as a whole is more It is set larger than the indoor heat exchanger 5.
In other words, because the indoor heat exchanger 5 is smaller than the outdoor heat exchanger 22, the indoor heat exchanger 5 may increase the amount of gas refrigerant so that the condensate refrigerant does not accumulate in the indoor heat exchanger 5 as much as possible. Necessary. This is because when the amount of the condensate refrigerant increases, the heat exchange capacity of the portion where the liquid refrigerant is accumulated is lower than the portion where the gas refrigerant is accumulated.
[0014]
Here, the feature of the present invention is that the indoor heat exchanger 5 acting as a condenser controls the opening degree of the expansion valve 8 so that a large amount of condensate refrigerant does not accumulate in the indoor heat exchanger 5. Is to maximize the condensing capacity.
In FIG. 3, 30a, 30b, 30c, 30d, 30e, and 30f are heat exchange pipes having an inner diameter of 7 mm (described above), and are arranged in a stacked state in six stages. A shunt 6 is connected to the inlet side (at the time of heating) of these six heat exchange pipes 30a to 30f, and a collecting pipe 7 is connected to the outlet side (at the time of heating). 31 is a controller for controlling the electric expansion valve 8. 32 is a temperature sensor attached to the heat exchange pipe 30b on the second stage (upper stage) side, detects the temperature of the refrigerant flowing in the heat exchange pipe 30b with this sensor, sends the value to the controller 31, The controller 31 sets the opening based on this value and transmits it to the electric expansion valve 8.
[0015]
Considering the pressure state in each heat exchange pipe 30a-30f, it is as follows. That is, the heat exchange pipe 30f on the 6th (lower) side is closer to the outlet 33 of the collecting pipe 7 than the heat exchange pipes 30a and 30b on the 1st or 2nd (upper) side. The pressure F in the heat exchange pipe 30f is low, and the pressures A and B in the heat exchange pipes 30a and 30b on the first stage or the second stage (upper stage) are increased. This is because the pipe resistance in the collecting pipe 7, gravity, and the flow direction of the refrigerant.
[0016]
Therefore, the gaseous refrigerant distributed by the flow divider 6 and flowing into the heat exchange pipes 30a to 30f is condensed in the heat exchange pipes 30a to 30f and is liquefied, and the heat exchange pipes 30a and 30b on the upper stage side. Since the refrigerant pressures A and B are higher than the refrigerant pressure F in the lower heat exchanger pipe 30f, the liquid refrigerant in the upper heat exchange pipes 30a and 30b is smoothly led to the collecting pipe 7. It is burned. However, the liquid refrigerant in the lower heat exchange pipe 30f is easily stored in the pipe 30f because the pressure F is low as described above.
[0017]
In such a state, since the sensor 32 is provided in the upper heat exchange pipe 30b in this state, the temperature of the gas refrigerant can be reliably detected, and the opening degree of the expansion valve 8 is controlled based on this detection. To do. That is, when the temperature of the gas refrigerant decreases, the opening degree of the electric expansion valve 8 is increased (opened) via the controller 31 so that the refrigerant accumulated in the indoor heat exchanger 5 is reduced. The air is forced to flow to the outdoor heat exchanger 22. Thereby, the inside of the indoor heat exchanger (condenser) 5 becomes only a gas refrigerant, and the heat exchange capability of the condenser 5 can be increased.
[0018]
In particular, when such a control is used for a heat pump type air conditioner as in this embodiment, the heat exchange capability of the indoor heat exchanger 5 that acts as a condenser during heating can be sufficiently exhibited. It can be matched to the Japanese climate, which requires more heating capacity than cooling capacity.
Needless to say, the present invention is not limited to the above-described heat pump air conditioner, and can also be applied to a normal refrigeration apparatus.
[0019]
【The invention's effect】
As described above, the present invention flows the gas refrigerant discharged from the compressor to each heat exchange pipe of the condenser via the flow divider, and collects the refrigerant condensed by these heat exchange pipes in the collecting pipe. After that, in the refrigeration system that depressurizes with an expansion valve and leads to the evaporator, these heat exchange pipes meander in the same shape in the condenser, and these heat exchange pipes are arranged in a stacked state vertically. In addition, a sensor for controlling the opening degree of the expansion valve is provided in the upper heat exchange pipe connected to the collecting pipe, and the opening degree of the expansion valve is controlled based on a value detected by the sensor. As a result, liquid refrigerant is less likely to accumulate in this condenser, and the capacity of the condenser can be fully exhibited. This can also promote downsizing of the condenser.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an internal structure of an air conditioner (refrigeration apparatus) according to the present invention.
FIG. 2 is a refrigerant circuit diagram of the air conditioner shown in FIG.
FIG. 3 is an explanatory diagram showing a refrigerant flow during heating of the indoor heat exchanger shown in FIG. 2;
[Explanation of symbols]
5 Condenser 6 Divider 8 Expansion Valve 20 Compressors 30a-30f Heat Exchange Pipe 32 Sensor

Claims (1)

The gas refrigerant discharged from the compressor is caused to flow to the respective heat exchange pipes of the condenser via the flow divider, and the refrigerant condensed in these heat exchange pipes is collected in the collecting pipe, and then decompressed by the expansion valve and evaporated. In the refrigeration system leading to the condenser , these heat exchange pipes meander in substantially the same shape in the condenser, and these heat exchange pipes are arranged in a stacked state in the upper and lower sides, and on the upper stage side connected to the collecting pipe A refrigeration apparatus, wherein a heat exchange pipe is provided with a sensor for controlling the opening degree of the expansion valve.

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